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-rw-r--r--fs/block_dev.c74
-rw-r--r--fs/ioctl.c15
-rw-r--r--fs/super.c90
-rw-r--r--include/linux/fs.h2
4 files changed, 110 insertions, 71 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 39cb6591d37d..1aba036dcabf 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -245,38 +245,14 @@ struct super_block *freeze_bdev(struct block_device *bdev)
sb = get_active_super(bdev);
if (!sb)
goto out;
- down_write(&sb->s_umount);
- if (sb->s_flags & MS_RDONLY) {
- sb->s_frozen = SB_FREEZE_TRANS;
- up_write(&sb->s_umount);
+ error = freeze_super(sb);
+ if (error) {
+ deactivate_super(sb);
+ bdev->bd_fsfreeze_count--;
mutex_unlock(&bdev->bd_fsfreeze_mutex);
- return sb;
- }
-
- sb->s_frozen = SB_FREEZE_WRITE;
- smp_wmb();
-
- sync_filesystem(sb);
-
- sb->s_frozen = SB_FREEZE_TRANS;
- smp_wmb();
-
- sync_blockdev(sb->s_bdev);
-
- if (sb->s_op->freeze_fs) {
- error = sb->s_op->freeze_fs(sb);
- if (error) {
- printk(KERN_ERR
- "VFS:Filesystem freeze failed\n");
- sb->s_frozen = SB_UNFROZEN;
- deactivate_locked_super(sb);
- bdev->bd_fsfreeze_count--;
- mutex_unlock(&bdev->bd_fsfreeze_mutex);
- return ERR_PTR(error);
- }
+ return ERR_PTR(error);
}
- up_write(&sb->s_umount);
-
+ deactivate_super(sb);
out:
sync_blockdev(bdev);
mutex_unlock(&bdev->bd_fsfreeze_mutex);
@@ -297,40 +273,22 @@ int thaw_bdev(struct block_device *bdev, struct super_block *sb)
mutex_lock(&bdev->bd_fsfreeze_mutex);
if (!bdev->bd_fsfreeze_count)
- goto out_unlock;
+ goto out;
error = 0;
if (--bdev->bd_fsfreeze_count > 0)
- goto out_unlock;
+ goto out;
if (!sb)
- goto out_unlock;
-
- BUG_ON(sb->s_bdev != bdev);
- down_write(&sb->s_umount);
- if (sb->s_flags & MS_RDONLY)
- goto out_unfrozen;
-
- if (sb->s_op->unfreeze_fs) {
- error = sb->s_op->unfreeze_fs(sb);
- if (error) {
- printk(KERN_ERR
- "VFS:Filesystem thaw failed\n");
- sb->s_frozen = SB_FREEZE_TRANS;
- bdev->bd_fsfreeze_count++;
- mutex_unlock(&bdev->bd_fsfreeze_mutex);
- return error;
- }
- }
-
-out_unfrozen:
- sb->s_frozen = SB_UNFROZEN;
- smp_wmb();
- wake_up(&sb->s_wait_unfrozen);
+ goto out;
- if (sb)
- deactivate_locked_super(sb);
-out_unlock:
+ error = thaw_super(sb);
+ if (error) {
+ bdev->bd_fsfreeze_count++;
+ mutex_unlock(&bdev->bd_fsfreeze_mutex);
+ return error;
+ }
+out:
mutex_unlock(&bdev->bd_fsfreeze_mutex);
return 0;
}
diff --git a/fs/ioctl.c b/fs/ioctl.c
index 7faefb4da939..2d140a713861 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -525,15 +525,8 @@ static int ioctl_fsfreeze(struct file *filp)
if (sb->s_op->freeze_fs == NULL)
return -EOPNOTSUPP;
- /* If a blockdevice-backed filesystem isn't specified, return. */
- if (sb->s_bdev == NULL)
- return -EINVAL;
-
/* Freeze */
- sb = freeze_bdev(sb->s_bdev);
- if (IS_ERR(sb))
- return PTR_ERR(sb);
- return 0;
+ return freeze_super(sb);
}
static int ioctl_fsthaw(struct file *filp)
@@ -543,12 +536,8 @@ static int ioctl_fsthaw(struct file *filp)
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
- /* If a blockdevice-backed filesystem isn't specified, return EINVAL. */
- if (sb->s_bdev == NULL)
- return -EINVAL;
-
/* Thaw */
- return thaw_bdev(sb->s_bdev, sb);
+ return thaw_super(sb);
}
/*
diff --git a/fs/super.c b/fs/super.c
index c248ac6a1a21..89afca5055ab 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -944,6 +944,96 @@ out:
EXPORT_SYMBOL_GPL(vfs_kern_mount);
+/**
+ * freeze_super -- lock the filesystem and force it into a consistent state
+ * @super: the super to lock
+ *
+ * Syncs the super to make sure the filesystem is consistent and calls the fs's
+ * freeze_fs. Subsequent calls to this without first thawing the fs will return
+ * -EBUSY.
+ */
+int freeze_super(struct super_block *sb)
+{
+ int ret;
+
+ atomic_inc(&sb->s_active);
+ down_write(&sb->s_umount);
+ if (sb->s_frozen) {
+ deactivate_locked_super(sb);
+ return -EBUSY;
+ }
+
+ if (sb->s_flags & MS_RDONLY) {
+ sb->s_frozen = SB_FREEZE_TRANS;
+ smp_wmb();
+ up_write(&sb->s_umount);
+ return 0;
+ }
+
+ sb->s_frozen = SB_FREEZE_WRITE;
+ smp_wmb();
+
+ sync_filesystem(sb);
+
+ sb->s_frozen = SB_FREEZE_TRANS;
+ smp_wmb();
+
+ sync_blockdev(sb->s_bdev);
+ if (sb->s_op->freeze_fs) {
+ ret = sb->s_op->freeze_fs(sb);
+ if (ret) {
+ printk(KERN_ERR
+ "VFS:Filesystem freeze failed\n");
+ sb->s_frozen = SB_UNFROZEN;
+ deactivate_locked_super(sb);
+ return ret;
+ }
+ }
+ up_write(&sb->s_umount);
+ return 0;
+}
+EXPORT_SYMBOL(freeze_super);
+
+/**
+ * thaw_super -- unlock filesystem
+ * @sb: the super to thaw
+ *
+ * Unlocks the filesystem and marks it writeable again after freeze_super().
+ */
+int thaw_super(struct super_block *sb)
+{
+ int error;
+
+ down_write(&sb->s_umount);
+ if (sb->s_frozen == SB_UNFROZEN) {
+ up_write(&sb->s_umount);
+ return -EINVAL;
+ }
+
+ if (sb->s_flags & MS_RDONLY)
+ goto out;
+
+ if (sb->s_op->unfreeze_fs) {
+ error = sb->s_op->unfreeze_fs(sb);
+ if (error) {
+ printk(KERN_ERR
+ "VFS:Filesystem thaw failed\n");
+ sb->s_frozen = SB_FREEZE_TRANS;
+ up_write(&sb->s_umount);
+ return error;
+ }
+ }
+
+out:
+ sb->s_frozen = SB_UNFROZEN;
+ smp_wmb();
+ wake_up(&sb->s_wait_unfrozen);
+ deactivate_locked_super(sb);
+
+ return 0;
+}
+EXPORT_SYMBOL(thaw_super);
+
static struct vfsmount *fs_set_subtype(struct vfsmount *mnt, const char *fstype)
{
int err;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index eeb04ba17b63..d51256bc6328 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1797,6 +1797,8 @@ extern void drop_collected_mounts(struct vfsmount *);
extern int iterate_mounts(int (*)(struct vfsmount *, void *), void *,
struct vfsmount *);
extern int vfs_statfs(struct dentry *, struct kstatfs *);
+extern int freeze_super(struct super_block *super);
+extern int thaw_super(struct super_block *super);
extern int current_umask(void);
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-29 08:41:47 +0000